如何从路径中提取文件名？

Question

The path from which I want to extract the filename takes the form:

C:\Folder1\Folder2\Folder3\Folder4\Folder5\x.png

This should give x (I do not need the extension). The file is always a PNG file. x can be 1, 2, 3 or 4 digits, but can never contain any other character (only a number).

I tried a 'manual' method, which is working well.

function getId(x) {
  x = x.slice(0,-4);
  var str = "";
  var flag = 0;
  for(var i = x.length - 1; i >= 0; i--) {
    if(!isNaN(x[i])) {
      str = x[i] + str;
      flag = 1;
    } else if(flag == 1) {
      break;
    }
  }
  console.log(str);
}

Is there any simpler approach without using a library?

Answer 1

You could match one or more times a digit in a capturing group. Then match a dot and not a backslash one or more times using a negated character class and assert the end of the string.

(\\d+)\\.[^\\\\]+$

 const regex = /(\\d+)\\.[^\\\\]+$/; const str = "C:\\\\Folder1\\\\Folder2\\\\Folder3\\\\Folder4\\\\Folder5\\\\1.png"; console.log(str.match(regex)[1]); 

Answer 2

You can use split() and pop() to get the file name without extension:

 var file = 'C:\\\\Folder1\\\\Folder2\\\\Folder3\\\\Folder4\\\\Folder5\\\\x.png'; var fileName = file.split(/\\\\/).pop(); fileName = fileName.split('.')[0]; console.log(fileName); 

Answer 3

Not the best way, but so simple:

const str = 'C:\\Folder1\\Folder2\\Folder3\\Folder4\\Folder5\\t.png';
const getId = path => path.split('\\').pop().split('.')[0];
console.log(getId(str));